Disclosed in JP2002-119824A is an air dryer that dries a compressed air, which is obtained by compressing air by means of a compressor provided separately from the air dryer, and then sends the compressed and dried air to an air control system provided separately from the air dryer. According to the air dryer disclosed in JP2002-119824A, a housing, which is formed in a substantially cylindrical shape, includes a compressor-side port, which is connected to the compressor provided separately from the air dryer, at one end surface of the housing in an axial direction thereof and a system-side port, which is connected to the air control system, at the other end surface of the housing in the axial direction. Furthermore, the housing is filled with a desiccant (a drying agent). The desiccant, which is provided within the housing, dehumidifies the air passing through the housing from the compressor to the air control system. More specifically, when the air passes through the housing, moisture contained within the air is absorbed to the desiccant, thereby dehumidifying the compressed air. Generally, a dehumidifying function of the desiccant gradually decreases as an amount of moisture absorbed by the desiccant increases. Therefore, in order to continuously use the air dryer, the air, which has already dehumidified and which exists within the air control system, needs to be returned to the compressor via the air dryer, so that the moisture absorbed in the desiccant is returned to the dry air in order to reduce the amount of the moisture absorbed to the desiccant, thereby restoring the desiccant. As a result, the dehumidifying function of the air dryer is restored. Additionally, the air dryer disclosed in JP2002-119824A may still remove moisture condensed within the housing even in a case where the air dryer is transversely arranged within a vehicle and like.
Disclosed in JPH7-328373A is a moisture removing device that includes a liquid separator and a dryer. The liquid separator includes a tangential inflow type cyclone, into which air containing moisture in a vapor phase and a liquid phase flows, and a water recovering housing defining a passage expanding chamber. Furthermore, an inner cylinder of the cyclone, whose passage is enlarged towards an opening portion thereof, protrudes towards the passage expanding chamber. An annular groove for collecting liquid moisture is formed around the inner cylinder, which protrudes towards the passage expanding chamber. The dryer is provided at a downstream side of the flow of the air relative to the liquid separator and is filled with solid desiccant.
Disclosed in JPH5-201329A is an air-hydraulic composite brake system for a vehicle in which a compressed air, which is obtained by compressing air by means of an air compressor, is stored within an air tank and a braking operation is performed by the compressed air on the basis of an operation of a brake pedal. Furthermore, JPH5-201329A discloses a configuration in which the air-hydraulic composite brake system includes an air dryer for removing moisture contained in the compressed air by means of a desiccant and an electrostatic purifier for removing oil mist contained in the compressed air at a prior stage of drying the air. The oil mist is removed from the compressed air, which is obtained by compressing the air by means of the air compressor, by the electrostatic purifier, and then, the compressed air is stored within the air tank. Additionally, there exist various vapor-liquid separating devices.
The dryer disclosed in JP2002-119824A is relatively large, therefore, a relatively large space needs to be prepared at the vehicle in order to mount the dryer thereto. The cyclone type dryer disclosed in JPH7-328373A and the electrostatic type dryer disclosed in JPH5-201329A have relatively complex structures and manufacturing costs are relatively high.
A need thus exists to provide a dryer for an air suspension for a vehicle which is not susceptible to the drawback mentioned above.